The present invention relates to bar code readers and more specifically to an off-scale item sensing apparatus and method for a bar code reader.
Bar code readers are well known for their usefulness in retail checkout and inventory control. Bar code readers mounted within checkout counters generally employ a laser diode, the light from which is focused and collimated to produce a scanning beam. An optical transceiver directs the beam against a mirrored polygon or spinner and then against a plurality of stationary mirrors, and collects the beam after it is reflected by a bar code label. A motor rotates the mirrored polygon, and a detector receives the returning beam. The pattern produced by such a bar code reader is characterized by lines oriented at various angles to one another.
Bar code readers also typically include a scale apparatus for measuring weights of produce and other items without bar codes. The scale apparatus typically includes a load cell and a weigh plate which rests on the load cell. The weigh plate is typically flush-mounted with the top surface of the checkout counter.
Unfortunately, a flush-mounted weigh plate exposes retailers to a risk of losing money from sales involving inaccurately weighed items. If an item rests partly on the top surface of the checkout counter, the scale records a weight less than the actual weight of the item.
Therefore, it would be desirable to provide an apparatus for a bar code reader which would detect an item that is not fully supported by the scale weigh plate and provide an indication to an operator of the bar code reader to relocate the item to a position totally supported by the weigh plate.